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Lead species formation on pure hemimorphite surface and its performance for subsequent sulfidization

Liang Guanyu, Zhang Song, Xian Yongjun, Chen Luzheng

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 2

art. no. 187064

EN

Hemimorphite is important-supplementary resource for the commercial zinc production, but it easy loses into tailings due to extreme difficulty for its surface sulfidization. Adding active metal ions after sulfidization have been widely proposed for enhancing hemimorphite floatability, but its desired efficiency in flotation practice has not yet been completely achieved caused by the instability of sulfide layer. Whereas pre-adsorption of active metal ions to modify the hemimorphite surface has strong potential to make up for this shortcoming. Herein, the feasibility and appropriate environment of free Pb2+ for modifying the pure hemimorphite surface was evaluated. Subsequently, the performance of Pb2+ adsorption for enhancing sulfidization stability and floatability of hemimorphite were investigated. The X-ray photoelectron spectroscopy results indicated that the Pb2+ adsorption on hemimorphite surface was achieved through the Pb ions displacement for Zn ions, and it was bond to oxygen-containing groups on hemimorphite surface. Such adsorption was strengthened with the increasing of solution pH, owing to the abundant Pb hydroxyl species precipitated on mineral under alkaline conditions, in term of the results of visual MINTEQ modeling and time-of-flight secondary-ion mass spectrometry. In addition, the X-ray photoelectron spectroscopy results showed dominant Pb hydroxyl species further reacted with sulfur during subsequent sulfidization to generate much more S species than that of without Pb2+ pre-modification. Meanwhile, such sulfide layer composed by Pb2+ on the mineral surface presented much higher stability than Zn-S species, which was verified via adsorption and desorption tests. As a result, the sulfidization and flotation recovery of hemimorphite increased after Pb2+ pre-adsorption.

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Dissolution kinetics of hemimorphite in methane sulfonic acid

Zhang Qian, Wen Shuming, Feng Qicheng, Nie Wenlin, Wu Dandan

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 1

1--9

EN

Hemimorphite has a large content of zinc, but its recovery using flotation alone is low. Nowadays, hydrometallurgical and pyrometallurgical methods are used to treat zinc ores. In this work, the leaching and dissolution kinetics of hemimorphite by using methane sulfonic acid (MSA) as an alternative leaching reagent was investigated. The effects of several experimental parameters including reaction temperature, MSA concentration, particle size, and stirring speed were also analyzed. Results showed that zinc leaching increased with increased reaction temperature, MSA concentration, and stirring speed, as well as decreased particle size. The mechanism of hemimorphite dissolution in MSA solutions may be a new variant of the shrinking-core model. Based on experimental data and kinetics, the apparent activation energy was determined to be 49.50 kJ/mol. The rate of reaction equation was also obtained to describe the process and found that the MSA concentration largely influenced the leaching of hemimorphite.

3

Geochemical and mineralogical characteristics of calamines from the Olkusz zinc and lead ore district (South Poland)

Swęd Maciej Krzysztof, Duczmal-Czernikiewicz Agata

Geological Quarterly

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2019

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Vol. 63, No. 4

699--710

EN

The mineralogical and geochemical characteristics of calamines developed from chemical weathering within two different tectonic settings (tectonic horst and graben) are described. Calamines collected from the Olkusz-Pomorzany and the Bolesław zinc and lead mines were analysed geochemically by means of EMP and SEM-EDS and their mineralogical composition was identified by using reflected light microscopy and XRD analysis. The calamines from the Olkusz-Pomorzany mine are composed of marcasite, galena, cerussite, sphalerite, hemimorphite, smithsonite and goethite. Hemimorphite prevails over smithsonite and occurs in the vicinity of primary sulphides. The mineralogical composition of the calamines from the Bolesław area is less diverse. These are primarily composed of goethite and smithsonite, with a minor content of marcasite and remnant sphalerite. The mineral composition of weathering sites in the Olkusz-Pomorzany and Bolesław areas may reflect different geochemical conditions (from slightly acidic to alkaline pH values, from lower to higher CO2 partial pressure and solutions of different silica saturation) that could have changed over time. The mineralogical compositions of the calamines differ quantitatively and this could reflect the tectonic setting of the primary ore affecting the rate of chemical weathering.